1. Field of the Invention
The present invention relates in general to an internal combustion engine for a motor vehicle, and in particular to a cross-flow type internal combustion engine having an exhaust gas recirculation system capable of feeding a portion of the exhaust gases of the engine into the intake of the engine.
2. Description of the Prior Art
In order to suppress the formation of nitrogen oxides, (NO.sub.x) in the exhaust gases from the internal combustion engine, a so-called "exhaust gas recirculation (or EGR) system" is widely used in which a portion of the exhaust gases is fed, during engine operation, into the engine via an intake manifold. With this procedure, the combustion temperature in each combustion chamber is considerably lowered to inhibit production of nitrogen oxides (NO.sub.x). Usually, the EGR system hitherto employed comprises a separate metal tube which connects the interior of the exhaust manifold with that of the intake manifold and a flow controller disposed at a suitable portion of the tube. In fitting such EGR systems to a cross-flow type internal combustion engine, however, the conduit must be so arranged to extend over the engine thereby requiring a long tube. Employing such separate long tubes as part of the EGR system promotes condensation of exhaust gas components in the tube, because of the considerable cooling effect possessed by the tube, thereby rusting the tube. Further, employment of long conduit tubes causes bulky construction of the engine system, inevitably reducing the space available in the engine compartment of the motor vehicle and causing poor responsiveness in controlling the flow rate of recirculated gas with the flow controller.